Structural properties of [Cu(II)3L6] cages: bridged polyatomic anion effects on unprecedented efficiency of heterogeneous catechol oxidation

Self-assembly of CuX₂ (X^- = BF₄^-, ClO₄^-, PF₆^-, and SbF₆^-) with a bidentate ethylmethylbis(3-pyridine)silane ligand (L) in the presence of additional polyatomic anions (X' = SiF₆^2- and PF₆^-) gives rise to single crystals consisting of the X'@[Cu(II)₃L₆] cage motif. These cages exist as discrete or anion-bridged 3D networks depending on outside anions. The anion-bridged 3D networks interpenetrate in a four-fold fashion, and show, to our best knowledge, the most effective heterogeneous catalysis in 3,5-di-tert-butylcatechol oxidation reaction within 20 min at room temperature. Surprisingly, the heterogeneous catalysis is more effective than its corresponding homogeneous catalysis. Such notable catalytic effects can be explained by the maintenance of 3D inter-cage Cu⋯Cu distance as a catalytic center.

Hexanuclear Cu3O-3Cu triazole-based units as novel core motifs for high nuclearity copper(ii) frameworks

The asymmetric 3,5-disubstituted 1,2,4-triazole ligand H₂V (5-amino-3-picolinamido-1,2,4-triazole) by reaction with an excess of Cu(ii) perchlorate (Cu : H₂V being 12 : 1) has produced a novel hexanuclear {Cu₆(μ₃-O/H)(HV/V)₃} fragment, with one triangular Cu₃(μ₃-O/H) group connected to three peripheral single Cu(ii) ions through a cis-cis-trans bridging mode of the ligand, which is the building block of the three structures described here: one hexanuclear, [Cu₆(μ₃-O)(HV)₃(ClO₄)₇(H₂O)₉]·8H₂O (1), one dodecanuclear, [Cu₁₂(μ₃-O)₂(V)₆(ClO₄)₅(H₂O)₁₈](ClO₄)₃·6H₂O (2), and one tetradecanuclear 1D-polymer, {[Cu₁₄(μ₃-OH)₂(V)₆(HV)(ClO₄)₁₁(H₂O)₂₀](ClO₄)₂·14H₂O} _n (3), the last two containing hexanuclear subunits linked by perchlorato bridges. The Cu-Cu av. intra-triangle distance is 3.352(2) Å and the Cu(central)-Cu(bridged external) av. distance is 5.338(3) Å. The magnetic properties of the hexanuclear "Cu₃O-3Cu" cluster have been studied, resulting as best fit parameters: g = 2.18(1), J(intra-triangle) = -247.0(1) cm^-1 and j(central Cu^II - external Cu^II) = -5.15(2) cm^-1.

Interactions between H-bonded [CuII3(μ3-OH)] triangles; a combined magnetic susceptibility and EPR study

X-band EPR spectroscopy and magnetic susceptibility studies elucidate the magnetic exchange scheme within a triangular CuII3(μ₃-OH) complex and the intermolecular dipolar interactions between two H-bonded CuII3(μ₃-OH) units.

A discrete CuII6 cluster and a 3D MnII–CuII framework based on assembly of Mn2Cu4 clusters: synthesis, structure and magnetic properties

Two new magnetic metal–organic coordination compounds, a 0D Cu₆ cluster and a 3D heterometallic framework with MnII2CuII4 secondary building units are synthesized. Detailed magnetic studies are performed with proper magneto-structural correlation.

A one-dimensional coordination polymer based on Cu3-oximato metallacrowns bridged by benzene-1,4-dicarboxylato ligands: structure and magnetic properties

A one-dimensional linear coordination polymer {[Cu₃(μ₃-OH)(2-pyao)₃(bdc)]·6(H₂O)}_n (1) composed of trinuclear metallacrown cores has been obtained.

Four new trinuclear {Cu3(μ3-OH)(oximate)3}2+ clusters: crystal structure and magnetic behaviour

Four new triangular copper(ii) complexes with the fragment {Cu₃(μ₃-OH)(oximate)₃}²⁺ are reported. They exhibit strong antiferromagnetic coupling and antisymmetric exchange interaction.

pH dependent facile synthesis of di- and trinuclear oxime based Cu(ii) complexes: antiferromagnetic coupling in the dinuclear cores and spin frustration in the triangular core

Two antiferromagnetic dinuclear and one spin frustrated trinuclear cores of oxime based Cu(ii) compounds have been synthesized by changing the pH of the reaction mixtures.